Abstract: Plant communities of Leymus chinensis,L.chinensis-Artimisia frigida,Stipa grandis,S.krylovii,and A.intramongolica were transported into experimental station from the field keeping their previous states.The soils were carefully moved with aboveground plants with a depth of 30cm.Soil respiration rate were measured by dynamic chamber/IRGA methods during the main growth period of communities(from later May to later August).The results showed that the soil respiration were significant difference with diurnal and seasonal dynamics.The aboveground biomass and soil respiration were closely correlated of Artimisia community.The rate of soil CO₂ release from A.intramongolica community was consistently lower than other communities,and L.chinensis was higher.only for A.intramongoica was aboveground biomass highly positively correlated with seasonal soil respiration.Temperatures of air and soil had effects on diurnal and seasonal CO₂ release rate.Temperature of 50cm soil layers explained most of the variance of soil respiration.Soil water content had little influence on soil respiration of A.intramongolica communities while it controlled the soil bioactivities of other communities.

Key words: Grassland, Community, Soil respiration, Temperature

摘要： 从野外选取有代表性的羊草、羊草-冷蒿、大针茅、克氏针茅和沙蒿群落,原状移栽到试验场。采用动态气室/IRGA法在植物主要生长期,连续测定各群落的土壤呼吸。结果表明,土壤呼吸速率具有明显的昼夜变化和季节动态。沙蒿群落土壤呼吸速率和土壤CO₂排放总量低于其它群落,羊草群落CO₂日排放量和CO₂总排放量较高。沙蒿群落地上部生物量与土壤呼吸呈高度正相关。气温和土壤温度对CO₂排放速度日变化及季节变化都有一定的影响,其中地温能解释土壤呼吸变异的绝大部分。水分对沙蒿群落的影响不大,但对羊草等群落的土壤生物活性有控制作用。

关键词: 草地, 群落, 土壤呼吸, 温度